Basil leaves curling up


First grow problem – Edges of leaves are curling up?

Question: What do I do if the edges of my cannabis leaves are curling up?

Take a look

Only one of my 3 plants is having this issue.

A friend suggestted that the issue may be low humidity.

I live in a dry area so the humidity in my house is normally below 20%. However, when I checked the humidty in my grow tent, it was 36% so I’m not actually sure it’s actually too low.

Any ideas of anything else I should check?

More grow details: 250W HID, 2x3x5 grow tent with 4″ inline fan. Northern Lights strain. Seeds germinated in rockwool and transplanted into 4 gallon smart pots w/ mix of peat moss and perlite. Fox Farms Nutrient Trio for nutes – following the dosing schedule but started with 1/2 doses for the first week. pH of water is 6.5-6.6 and runoff from pots tested at 6.4-6.6.

Answer: Heat stress, Root Problems or Extreme Humidity

This looks like the result of excessive heat, root problems (possibly from overwatering) and/or suffering from extreme humidity levels (such as very high or low humidity).

When the the serrated edges of marijuana leaves curls or tipped up like that, it’s often a sign of temperature stress, overwatering/root problems or extreme humidity levels. This plant was overwatered and living in high heat, which is what caused these symptoms.

When the problem is low humidity, the leaf will also often fold in the middle, like a taco.

What’s your temperature in your grow area? Is there a hot spot around these plants from the grow light?

You mentioned that this is happening to only some of your plants. If this is happening to the plants which are closest to your grow light, that’s a hint that the problem may be temperature related.

If your light is simply too close, you can move the bulb further away from these plants and this issue may resolve itself. However, these leaves are showing symptoms of heat stress, without light stress (burning / spotting), so it’s more likely that the light is a good distance away and the heat just isn’t being controlled properly.

If plants are also droopy, it’s likely you’re dealing with watering or root problems.

When growing with hot HID lights, good ventillation and an exhaust fan will go a long way towards preventing all these problems. If the whole grow area is too hot with stagnant air, you will want to consider venting out all that extra heat.

Having good air movement, like a small fan in your grow tent blowing over the tops of your plants, can help prevent hot spots from forming directly under your grow lights.

In general, if it’s too hot for you to be comfortable, it’s too hot for your plants.

Learn More About Cannabis Heat Stress

Learn More About Root Problems

Learn About Controlling Humidity

Jump to…

Leaf tips turned down? It may be a Nitrogen Toxicity
How to Set Up / Vent Heat with HID Grow Lights
Check These 7 Things & Cure 99% of Marijuana Growing Problems
1st Grow in My Garage – Auto Northern Lights in Grow Box Under 400W HPS

My Basil Leaves Are Curling – Why Do Basil Leaves Curl Under

Help! My basil leaves are curling and I don’t know what to do! Why do basil leaves curl under? The reason for basil leaves curling up may be environmental, or your plant may be diseased or pestered by pests. Read on to learn more about this frustrating problem.

Reasons for Basil Leaves Curling Up

Generally, growing basil in the garden is easy and stress-free. That being said, problems can and do arise. Basil leaf curl treatment is dependent on the specific factor causing it. Here are the most common stressors leading to curling basil leaves.

Sunlight – Basil is definitely a sun-loving plant and exposure to less than six hours of bright light per day may result in distorted foliage or basil leaves small and curled. Relocating the plant to a sunnier location may solve the problem.

Water: Too much or too little – Basil requires regular water, but not too much. As a general rule, water the plant deeply whenever the top 1 to 2 inches (2.5-5 cm.) of soil feels dry to the touch, usually once every four to seven days. However, keep in mind that potted plants may require more frequent irrigation, especially during hot, dry weather.

Whether the plant is in the ground or in a container, be sure the soil (or potting mix) is lightweight and drains well. Water at the base of the plant and keep the leaves as dry as possible.

Diseases – Fungal diseases may be the cause of basil leaves curling up, but chances are, you’ll notice other telltale signs. For example, powdery mildew is a fungal disease that causes a grey, powdery substance on the leaves. The disease is caused when conditions become too moist, including too much shade or soggy soil.

Fusarium wilt, which is usually deadly, can cause brown or distorted leaves. To prevent moisture related diseases, water basil carefully as directed above.

Pests – Basil is a hardy plant, but it can sometimes be bothered by aphids and other small, sap-sucking pests such as spider mites or scale. The pests can be difficult to see, but a close look at the leaves, especially the undersides, will usually tell the tale.

If you determine your plant is infested with bugs, insecticidal soap spray usually keeps the pests in check. Be sure to spray when the foliage is in the shade; otherwise, the spray may scorch the plant. Don’t spray when the temperatures are above 90 degrees F. (32 C.).

Basil leaves curling up lengthwise

Hi everyone,
I’m new here and seeking some advice on how to save my basil plant. I started this plant from a cutting, which was actually condiment from a vietnamese pho restaurant.
I planted it outdoors in the spring along with some thai basil that I picked up form the nursery. Although my internet research tells me that the basil that comes with pho is indeed thai basil, the plant I got from the nursery just wasn’t the same. But I digress. Both plants were started in the spring, but while the store-bought plant grew quite prolifically, the basil from the cutting didn’t seem to budge. I thought it would surely die, but it seemed to hold up albeit being exactly the same size as when it was potted.
I recently brought it inside to brave the winter and decided to feed it with an all purpose plant food. They day after, the leaves started to curl upwards as you can see in this photo . There are also some brown spots that appeared before I brought it inside.
It’s sitting in front of a south-facing window and I water it only when the soil gets dry on top. I’m sure I mixed the plant food correctly, so I’m not sure why the leaves have decided to curl up all of a sudden. Any ideas why? Advice?
Also, the plant is in pretty bad shape in general and never seems to grow. Thoughts?

11 Little Known But Effective Growing Tips For Basil

Plants are living organisms, just like humans, and let’s face it, just like
“eating and sleeping” is an over-simplified plan for you to stay healthy,
“planting and watering” is not enough for growing healthy plants,
especially in small scale urban farms with limited space and resources.

The truth is, taking care of an urban farm as a beginner can be just as challenging as taking care of a growing human being for the first time (seriously).
So what do you do if you are a new to growing basil in your urban growing operation and you believe you took all of the right cultivation steps, but the plants are not growing as expected?
(continue reading)

Is this a mistake you made?
Probably not. The reality is that growing crops can be an incredibly complex process, especially when you are just starting out as a grower.

But never fear, these common 11 farm proven secrets to troubleshooting basil growing should provide pointers to get your basil back on track.

Growing basil completely indoors is challenging. One alternative for urban growers is to grow part inside and part outside

1. Your basil leaves do not look as healthy as they
should, despite the fact that you are providing optimal levels of light for basil and watering regularly.

If basil leaves are well colored and maintaining weight, but are less spry than you had hoped, even after proper light exposure and soil, the issue may be overwatering.
Although basil prefers more moisture in its growing medium, and tends to be considered a warm weather herb, it can be easy to over-water, shoot for approximately 1 inch per week and reduce by a quarter-inch to see what happens.

2. Your basil plants are exclusively grown indoors,
and adapted outdoor growing instructions are not translating well, despite similar light exposure and temperature.

Generally speaking, growing basil can be much more difficult indoors if the conditions are not right.
Focus on optimizing light conditions for growing basil as much as possible, and be sure that you keep basil plants away from exterior windows at night (less warmth in most climates) and near sinks or drains (more moisture). Humidifiers can be used to prevent dry air in the growing space.
Last, indoor growing leaves plants at greater risk for root rot, because soil tends to drain less efficiently indoors. For this reason, ensure proper drainage of soil indoors, growing in clay pots instead of plastic can increase draining efficiency, but watch out for over-drying!

3. You began to grow your basil inside, then moved it outside, and you have noticed extreme wilting (the top of the plant may be touching the top soil)

There is nothing wrong with starting off basil plants indoors and transitioning outside, however keep in mind that just like your eyes need adjustment to indoor and outdoor light, basil plants likewise need a light adjustment period.
Instead of immediately exposing newly outside basil plants to 6-8 hours of direct light, start with a couple hours or even less time of direct light, and slowly transition over the course of a week or two from mostly shade to more direct light. This process is referred to as “hardening off” the basil plant, and is best practice with many types of seedlings transitioning from indoor to outdoor, not just basil.

Basil plants can be notoriously difficult to grow indoors.

4. You buried a “biodegradable” peat pot to grow your basil, and it is not developing as you hoped.

The extent of use of peat pots has long been a debate for basil growers, both in urban settings and beyond.
Generally speaking, you should remove peat pots as soon as possible, and they should not be buried with basil seedlings, as they stunt growth in part due to packing the soil to tightly for optimal root growth (this in turn causes drainage issues as discussed before).
If plant has yet to grow through the bottom / any holes in the peat pot, remove as much of the peat pot as you can and replant.

5. You planted your basil over a month ago, have
been watering regularly, and so far no results. What should you do?

In this case, you should seriously consider starting over. After 5+ weeks, no sprouting in basil is not a good sign.
If growing indoors, one strategy you can try is to grow outdoors to start (a more favorable environment for growing basil in most climates during the summer months) and then move indoors.
This will allow you to validate your growing practices in easier conditions.

6. You have started to grow your basil plants for
the first time, and all seems well. But there is one issue: brown grain-like objects are accumulating on the top soil or drainage tray. Should you be worried?

This is a likely sign of basil-loving worms that will eat and or damage your basil leaves. The first step is to try is to remove any residual worms or residue after careful inspection.
Depending on the state of the plant maturity, you may elect to harvest all available
leaves to be safe.

7. The leaves on your basil plant are thin and coarse, and in some cases are rolling up.

Basil does love heat, but not too much. This may be a sign of overheating. As a general rule, “leaf-curling” in basil is a sign of stress, whether that is from improper watering, light, or temperature, often in excess.

Leaf curling is a sign of stress in basil, which often times is triggered by overheating.

8. The leaves on your basil are small and stunted,
what is the cause?

As a general rule, basil leaf size is related to how optimized light exposure is
for the plant. Small leaves may be a sign to tone it down a bit on the direct

9. There is white film-like substance appearing on the top soil of your basil plant, is this harmful for growth?

Most of the time this white film is harmless bacteria that develops due to particles in the air. Simply clearing the film or turning the topsoil will take care of the issue.

10. There are little white flies on your basil plant,
are they dangerous, what do you do to get rid of them?

“Whiteflies” are a common pest in basil growing operations. If you have space in your urban growing area, one viable solution is to grow your basil with complimentary herbs such as oregano, which can help repel whiteflies.
Additionally, there are special insecticidal oils that can provide more of a quick fix to the issue, especially for smaller growing confines.

11. Your basil leaves were healthy and green, and
now parts of the plant are turning black. What do you do?

This is almost certainly a temperature issue. Although basil is challenging to grow well indoors, if the temperature conditions are more constant indoors, you should consider moving basil plants inside to prevent further cold damages.
Get rid of any black leaves just as you would get rid of any flowering. Keep in mind that black discoloration is not to be mistaken with purple discoloration. Purple coloration is often associated with the genetics of the basil plant in question, and usually does not indicate exposure to overly chilly temperature.

Bonus: 12. You are growing basil on a small scale for the first time. What are some basic tips so you do not mess this up (at least, completely)?

Water your basil regularly, at least every 3 days, for a total of 1 inch per week.
Ensure that the soil is well drained, using clay pots can help with drainage as
well as drainage holes regardless of pot composition.
Examine the leaves to gauge how adequately you are watering: If leaves appear light and wilted, you should likely water more, however if leaves appear to have solid weight and
color but look less supple than ideal, this may be a sign of over-watering.

Why Are My Weed Leaves Curling Up: Causes & Solutions

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Growing marijuana is truly a joy, well, except when you notice that your weed plants are having some health issues. There are many health issues which a weed plant can have. You might have noticed that your cannabis plant is suffering from leaves that are curling upwards, and possibly discolored too.

So, why are my weed leaves curling up? Well, this could be due to a number of issues, and most commonly, under or over water your plant, giving it far too much nutrients, or excessive heat or cold are the main causes of curled up cannabis leaves, among others.

There are 6 main causes of curling up cannabis leaves, and today we want to talk about each of them, as well as the solutions to each problem.

Why Are My Weed Leaves Curling: Causes & Solutions

Ok, so there are a few different reasons why your cannabis plant leaves might be curling up, and they vary greatly.

Let’s go over the 6 main causes of curled up weed leaves, and what you can do to remedy the problems.

1. Excessive Heat or Cold

One of the issues which can cause your cannabis plant leaves to curl up is due to excessive heat. If your cannabis plants are in a grow room or an environment that is too hot, you will often see the leaves curl up and develop nasty looking brown fringes.

Most cannabis plants require the temperature to be well below 30 degrees Celsius, usually more like 27 or 28 degrees. Anything over 30 degrees Celsius can cause heat stress, which results in curled and yellowing or browning leaves, among a host of other problems. Simply put, your pot plant is burning up due to being too hot.

On the other hand, excessive cold has also been known to cause curly cannabis leaves. Pot plants should never be in temperatures below 12 or 10 degrees Celesius at the lowest.

If your pot plant is regularly subjected to excessive cold, the leaves can become very discolored, they can curl up, bud rot may develop, and eventually your plant will just die.

The Solution

The solution to these temperature issues can vary depending on what the exact problem is. Either way, you need to ensure that your grow room is at the right temperature to support healthy weed growth.

One thing to keep in mind here is that weed plants require different temperatures based on the stage of growth they are in, whether this be the seedling, vegetative, or flowering stage.

General speaking, the optimal temperature range for cannabis across all of the growth stages is between 10 and 28 degrees Celsius.

Cannabis Plants Are Too Cold

So, if the grow room you have your cannabis plants in is too cold, here are some solutions you can try to put into effect.

Increase The Amount Of Grow Lights

Increase the amount of grow lights you have present, or replace current grow lights with stronger ones. The more light you have being produced in the grow room, the hotter the air will get. Keep in mind that certain types of grow lights put out more heat than others.

Turn Down Ventilation

If you have a lot of ventilation going on in your grow room, try turning that down. You might have to insulate holes and cracks in walls or doors to reduce airflow and to stop heat from escaping. You might also have to turn down your fans and ventilation systems, or even turn them off for a few hours. The more air circulation there is, and the more air can get out, the cooler the grow room will be.

Increase The Amount Of Reflective Materials

Increasing the amount of reflective materials present in the grow room will help reflect more light, and therefore will also hold more heat in the grow room.

Move Your Plants (If Outside Growing)

If you are growing outside, you might just have to move your plants indoors during the night to stop them from being exposed to the cold.

Cannabis Plants Are Too Hot

Just like there are various solutions to increase the temperature in your grow room, there are also ways to decrease the temperature in your grow room. Here are some solutions you can try to cool down your weed plants.

Try moving the plants further away from the grow lights, especially if you have ones that produce a lot of heat. Alternatively, you can try replacing your grow lights with certain types which do not produce as much heat.

Increase the amount of ventilation and air circulation you have in the grow room. The more air circulation there is, the cooler the grow room will get, plus this will help provide your pot plants with more oxygen as well. To do this, you can turn up an air fan, add an air fan to the mix, add more ventilation systems, or maybe drill a couple holes in the doors or walls to let heat escape.

Something to keep in mind here is that you can always try planting you cannabis in white pots or buckets, as opposed to black ones, which will absorb less light and therefore keep the roots cooler.

2. Too Little Or Too Much Water

Yet another cause of weed leaves curling up has to do with improper watering practices. Both under watering and over watering can cause this to occur, although most of the time it is over watering.

Generally speaking, beginner cannabis growers give their weed plants way too much water, but too little is usually not an issue. Keep in mind that given the situation, both under watering and over water can result in weed leaves curling either up or down. It really depends on the exact situation you have going on in your grow room.

Under watering your plant can also result in severe dehydration, it can combine with strong lights to burn the leaves, and it causes your plant dry out.

On the other hand, over watering can cause the roots of your plant to rot, which then causes it to not be able to absorb nutrients as it should.

Overwatering can also cause pest infestations, mold, and fungus. Simply put, over watering your plants will cause them to drown.

Ok, so the solution here is to start engaging in better watering practices, and this holds true whether you have been giving your cannabis plant too much or too little water. What you should do is the simple finger test.

If you stick your finger in the soil and you have wet soil sticking to your fingers, or if there is just a puddle of mud, it means you are over watering your plants. Let them dry out until the soil is quite dry until you water them again.

On the other hand, if you can stick your finger down into the soil a few inches and it is bone dry, you are under watering your plants. A good way to know if you are under watering your weed plants is if the leaves perk up right after you give them some water. (If you need some pointers on the right soil to use, checkout our epic guide here).

If you are under watering your plants, another solution may be too turn up the humidity a little bit, although this can be risky, as excessive humidity comes with its own issues.

3. Too Many Nutrients & Fertilizer

The next issue which can cause your cannabis leaves to curl up is if you are providing them with too many nutrients.

This tends to be the case mostly with nitrogen. Simply put, you could be poisoning and overwhelming your cannabis plant with too many nutrients.

This can then result in nutrient burn, often characterized by yellow, brown, and discolored leaves, combined with the curling up of the pot leaves.

If you have been following the directions on your plant nutrient bottle in regards to diluting the nutrients in water, you want to cut back a bit.

For instance, if you nutrient bottle calls for 2 teaspoons of nutrients per 2 gallons of water, cut back to ¼ or ½ a teaspoon per gallon. You might even want to eliminate nutrients for a couple of days altogether and use only water for feeding, to see if the problem resolves itself.

If this works, remember to use fewer nutrients than before, or else the problem will just start up again (more on the ideal nutrients here).

4. Wind Burn

Yes, your cannabis grow room should have some fans or a decent ventilation system, but there is such a thing as too much of a good thing.

In this case, weed plants require a bit of a breeze and some air circulation, but too much can cause leaves to curl up and look like they are burning. This is called wind burn.

The solution here is easy. Turn the fan down from the higher settings to the lower settings, and do the same with your ventilation system.

Moreover, try to aim the fan at a wall or just not directly at a weed plant. Even if you do not aim the fans at the plants, they will still create air circulation in your grow room.

If you are growing outdoors and it is excessively windy, you might just have to move the pot plants indoors.

5. Light Burn

Light burn is another thing which can cause your leaves to curl up. This generally happens at the top of your weed plants, and the closer to the light the plant is, the worse the problem can get.

Yes, weed plants need a lot of light, and some heat too, but once again, here we have the too much of a good thing problem again.

If you have excessively strong grow lights, too many of them, or depending on the type of light, if you have it too close to the pot plant, it can cause the leaves to burn, which is often characterized by the yellowing, drying out, and curling up of the leaves.

The solution to this issue comes in a few different forms. If you have a super strong industrial grow light, chances are you need to switch it out for something a bit smaller that does not put out so many lumens and so much heat.

Here, you can also try moving your plants further away from the lights, although this may cause them to stretch. You can also try taking down some of the reflective materials you have outfitted your grow room with, just to cut down on the amount of light reflection taking place.

Whatever you can do to decrease the amount and intensity of light your cannabis plants are getting should be undertaken if light burn is the issue.

6. Bugs & Other Pests

The other cause of curling leaves could be bugs and pests. There are certain bugs and pests which are known to cause the curling of cannabis leaves.

Due to the root, plant structural, and photosynthesis issues which many pests can cause, depending in the pest and severity of the infestation, it can cause curled up leaves.

There are fungus gnats, spider mites, and other pests which can cause this to occur.

This is a bit of a trickier problem to deal with, as different pests on your cannabis plants require different solutions, and often many solutions combined into one.

Using plant and people friendly natural pesticides, getting rid of severely infested plants, cutting off parts of the weed plant with severe infestations, and washing off your weed plants with various liquid mixes are all possible solutions to this problem.


Guys, if your cannabis leaves are curled up, it could be due to a number of issues, and each issue has various solutions you can try to put into effect. The point here is that you do need to get to the root of the problem as fast as you can, before it gets any worse, or else you risk the health of your plants, and of course the final yield and potency of your bud. Leave the problem for too long, and your cannabis plants might just die.

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